сократите дробь (7а^5)^8/(-49a^5)^4
(7а^5)^8 =( 7^8)*a^40
(-49a^5)^4 = ((7^2)^4)*a^20 =( 7^8)*a^20
( 7^8)*a^40/( 7^8)*a^20 = a^20